On Fri, 14 Apr 2000, Clay Cooke wrote:
>
> Yup, absolutely right. Ive run quite a few simulation programs for
> performance cars, I wrote the programs and they take into account
> everything from gear ratios to the inertia generated from the spinning
> gears, crank, etc etc. in other words they are VERY intense, and they
> encompass 99% of every aspect of vehicle operation and properties. Anyway,
> when running a corvette for top speed (stock vette by the way) and using
> all 6 gears, the top speed actually occurs in 5th gear, this is becuase
> the torque required from the engine to spin the drive train is to low at
> that point. So from the simulation the corvette would actually SLOW DOWN
> when it shifted into 6th, and according to the "while" loop used by the
> program it would then down shift into 5th gear and accelerate again.
>
> If you havent got the power to use it, why get it.
Yep, thats true. (And backed up by many many tests in magazines like
Car & Driver where top speed usually occurs in the 2nd to last gear, which
seems to be generally 1:1 and not overdriven.) I sure wouldn't mind a
6 speed though, as long as the gear ratios were set up right. Not for
top speed, but for acceleration and gas mileage. Before deciding to
go with an auto in my Dak, I was going to install a 6 speed, although
I couldn't find one with the ratios I wanted. Immagine having a .50:1
sixth gear... Install 4.56 or 5+ gears in the rearend... I think that
would result in an awesome holeshot and accelleration, but you can cruise
down the highway at nice comfortable RPMs getting decent gas mileage.
(Granted, with the driveshaft spinning faster'n a turbo...) ;-)
The problem I found with 6 speeds though is that (all the ones I
looked at) had 5th gear at 1:1 and 6th was the only overdriven gear.
I was looking for one with a 4th gear of 1:1, fifth around .75:1, and
a sixth of about .60:1 or .50:1. If fifth is 1:1, that doesn't really
do anything for you, except add another gear you have to shift through
to get to the same point where you were in 4th before! (read: your ETs
will probably drop!) This setup might be good on a road race vehicle
or a 4x4 where a wide range of gears is desireable, but not for my
needs. :-( Right now I'm planning on an auto, but I need to find a
way to get an overdrive while still maintaining strength and not
spending all my cash! (Those two objectives seem to be mutually
exclusive.) :-P
>
> But it would be sweet none the less!
Aye, that it would. :-) If for no other reason than to get nice
crisp shifts; this NV3500 is, after all, a truck transmission.
-Jon-
.--- jon@dakota-truck.net -- or -- stei0302@cs.fredonia.edu ------------.
| Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
| '92 Ram 150 4x4 V8, '96 Dakota V8, '96 Intruder 1400, '96 FireFly 447 |
`---------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'
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